Numbers 32:16-27

But they approached Moses and said, “We simply want to build pens for our livestock and fortified towns for our wives and children. Then we will arm ourselves and lead our fellow Israelites into battle until we have brought them safely to their land. Meanwhile, our families will stay in the fortified towns we build here, so they will be safe from any attacks by the local people. We will not return to our homes until all the people of Israel have received their portions of land. But we do not claim any of the land on the other side of the Jordan. We would rather live here on the east side and accept this as our grant of land.” Then Moses said, “If you keep your word and arm yourselves for the LORD’s battles, and if your troops cross the Jordan and keep fighting until the LORD has driven out his enemies, then you may return when the LORD has conquered the land. You will have fulfilled your duty to the LORD and to the rest of the people of Israel. And the land on the east side of the Jordan will be your property from the LORD. But if you fail to keep your word, then you will have sinned against the LORD, and you may be sure that your sin will find you out. Go ahead and build towns for your families and pens for your flocks, but do everything you have promised.” Then the men of Gad and Reuben replied, “We, your servants, will follow your instructions exactly. Our children, wives, flocks, and cattle will stay here in the towns of Gilead. But all who are able to bear arms will cross over to fight for the LORD, just as you have said.”